The purpose of this study is to determine whether interventions by a clinical pharmacist can improve drug use patterns in a elderly ambulatory population with polypharmacy. By enhancing patient compliance and reducing inappropriate prescribing, the health care of older patients could be improved. The two specific interventions to be evaluated are (1) the provision of medication counseling to patients and (2) the provision of educational feedback concerning drug regimens to primary care physicians. The research design is significant in that it will be the first randomized controlled trial to focus on a high risk population, that is, patients older than 70 years of age and on more than three medications. Outcome measures, such as medications taken, adverse drug reactions, compliance, health service utilization, medication costs, and health status, will be assessed before and after the implementation of the interventions. The ultimate objectives are to enhance the quality of health care of older patients and to assess the cost-effectiveness of a clinical pharmacist within an ambulatory setting.